The present invention relates to door frame assemblies, and in particular to an improved prefabricated door frame construction.
In the construction of interior walls such as those found in offices, and in certain exterior construction, the use of prefabricated metal door frames has become quite common. Such door frames generally consist of extrusions which are provided with slots or countersunk portions so that the hinge plates and strike plates can be conveniently installed. An example of such a door frame construction is depicted in the patent to Cable, U.S. Pat. No. 3,299,592. If the prefabricated door frame does not come from the factory with a provision for the installation of hinge plates and strike plates, the frame assembly must be cut at the construction site so that these items can be installed.
The door frame assemblies such as that described by Cable are not as convenient as desired for several reasons. The door frames must be provided in two models, one for left swinging doors and one for right swinging doors. Also, because the door frame construction determines where the hinges must be located, the hinges must be attached to the door at the construction site, and pre-hinged doors cannot be used. In addition, a separate model of door frame must be provided to accommodate the hinge and strike plate locations of doors of various shapes and sizes because the hinge and strike plate positions are fixed when the frame is fabricated.
In applicant's U.S. Pat. No. 3,287,856, a door frame assembly is depicted in which the hinges and strike plates can be located where desired at the construction site. Spaces between the hinge and strike plates are covered over with cover plate sections to provide an aesthetically pleasing finished construction. The principal difficulty with this type of assembly is that a certain amount of manual labor is still required to fix the hinge and strike plates to the door frame using conventional screw fasteners. Moreover, the construction of this door frame assembly is relatively complex because the cover plates and hinge strike plates are attached to the frame member using discrete connecting mechanisms, each of which must be accommodated by the door frame assembly.